package com.example.administrator.myapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
public class MainActivity extends AppCompatActivity {
private EditText e1;
private Button b1;
private Socket s = null;
private OutputStream out;
private String values;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
thread.start();
}
public void initView(){
e1 = findViewById(R.id.edit);
b1 = findViewById(R.id.btn);
b1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
values = e1.getText().toString();
try {
out.write(values.getBytes());
} catch (IOException e) {
e.printStackTrace();
}finally {
e1.setText("");
}
}
});
}
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
if(s == null){
try {
s = new Socket("172.18.11.103", 8000);
out = s.getOutputStream();
}catch (Exception e){
e.printStackTrace();
}
}
}
});
}
需求:從EditText獲取字符，通過Socket發送。
網路權限也加了，單擊就崩潰，哪里有問題嗎？
uj5u.com熱心網友回復：
看看報錯日志uj5u.com熱心網友回復：
09-03 20:35:51.745 5876-5876/com.example.administrator.myapplication2 E/AndroidRuntime: FATAL EXCEPTION: mainProcess: com.example.administrator.myapplication2, PID: 5876
java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.OutputStream.write(byte[])' on a null object reference
at com.example.administrator.myapplication2.MainActivity$1.onClick(MainActivity.java:36)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
09-03 20:35:51.854 406-2173/system_process E/[EGL-ERROR]: EGLBoolean __egl_platform_create_surface_window(egl_surface*, mali_base_ctx_handle):933: =========> usage 0x900
09-03 20:35:51.872 406-2173/system_process E/[EGL-ERROR]: EGLBoolean __egl_platform_create_surface_window(egl_surface*, mali_base_ctx_handle):933: =========> usage 0x900
uj5u.com熱心網友回復：
thread 沒有啟動 OutputSream 是空指標還有 不用開啟執行緒創建socket連接
write 內容的時候 可以考慮用執行緒死回圈讀取
uj5u.com熱心網友回復：
e1 控制元件沒有資料，out.write(values.getBytes());空參考因為values是空值，點擊按鈕前先在EditText e1 里填寫點資料;
轉載請註明出處，本文鏈接：https://www.uj5u.com/yidong/111298.html
標籤：Android